Cross section measurements of the pion single-charge-exchange reactionC12(π+,π0)12N(g.s.)

Abstract

Total cross sections for the pion single-charge-exchange reaction $^{12}\mathrm{C}$(${\mathrm{\ensuremath{\pi}}}^{+}$,${\mathrm{\ensuremath{\pi}}}^{0}$${)}^{12}$N (ground state) were measured at 116, 160, 180, 200, 230, and 291 MeV with a fast activation technique. The excitation function for this nonanalog, spin-flip transition was found to be flat over this energy region that includes the (3,3) resonance. Good agreement is noted between these measurements and the estimated cross sections obtained from pion inelastic scattering measurements for the analog reaction $^{12}\mathrm{C}$(${\mathrm{\ensuremath{\pi}}}^{+}$,${\mathrm{\ensuremath{\pi}}}^{+}$'${)}^{12}$${\mathrm{C}}^{\mathrm{*}}$ (${1}^{+}$,T=1,${\mathit{E}}_{\mathit{x}}$=15.1 MeV) for all energies except 230 MeV. Distorted-wave impulse-approximation calculations in the \ensuremath{\Delta}-hole formalism do not reproduce the trend of the data.